Question: Kira saw some spaceships in the sky. Then, she saw $6$ more. In total, she saw $12$ spaceships. How many spaceships did Kira see first?
Explanation: $ \begin{aligned}&{?} \text{ spaceships at first}\\ +& \underline{{6} \text{ more spaceships }}\\ =&{12} \text{ spaceships in total}\end{aligned}$ $6$ spaceships